Propshaft problem, please take a look

[stuhaynes]

The 8 inch lump in the pic's connects the gearbox to the propshaft, some kind of damper. Problem is that 3 of the 4 nuts at the front of the damper are very loose and the studs have stripped their threads. We have to remove the damper while the boat is still in the water.

Question is, can we remove the damper (in the water) to helicoil the threads? It will mean pushing the propshaft back by maybe 2 inches (maximum). What do you reckon? Sorry about pic quality.

It's not my boat and I don't want to screw it up for a mate.

The last pic clearly shows the loose nuts.

Thanks.

 

[cimo]

Only if i was confident the water would stay out, I'd give it a go.

Do you know for sure you'll have 2 inches clearance on the outside.
I notice your friend has a bolt missing on the stern gland's flange.

Can you undo both sides of the dampner and remove it completely, to avoid upsetting the shaft too much? i'd make arrangements to support the shaft's weight when uncoupled.

forgive me for prying, but is the stern gland really keeping out water as is, although the mounting bloack looks dry enough?

 

[daveyw]

................
forgive me for prying, but is the stern gland really keeping out water as is, although the mounting block looks dry enough?

I was wondering the same thing, in fact where the bolt is missing, has the stern tube actually moved. There looks to be a square impression offset from the sterntube mounting. I would be reluctant to slide the shaft back and forth too much unless the sterntube was secure.

 

[scottie]

I think that you have a metalastic coupling or similar

It has a central hub fastened to the shaft may be tapered which has 4 pins (1/2" dia) at right angles to the shaft a rubber bush goes over each of he pins there is a spit cast aluminium boss into which the four rubber bushes nest the boss will be held together with bolts running fore and aft and will have a cake tin cover

The front of the ally boss will be tapped to take the studs which fasten to the gear box half coupling

You may be able to disassemble the boss and remove coupling face to re tap the stud holes

Suggest you mark the boss before splitting to make sure it goes back on same as came off

Golden arrow marine may have more info and vetus have made similar units best of luck

 

[Spyro]

First what set up do you have outside? Is there a p bracket with a shaft anode? How close is it to the bracket?

Second I would think you are going to ruin any seal you have on the stern gland unless you clean up the shaft quite a bit before pushing it back. Chances are the shaft will be worn at the packing and you will be pushing a larger diameter section of shaft into the gland and widening the packing. Not a problem until you pull the shaft back to the original position. If you start getting more water in than expected you will need to adjust the gland or repack.

 

[stuhaynes]

New photo

I think that you have a metalastic coupling or similar

It has a central hub fastened to the shaft may be tapered which has 4 pins (1/2" dia) at right angles to the shaft a rubber bush goes over each of he pins there is a spit cast aluminium boss into which the four rubber bushes nest the boss will be held together with bolts running fore and aft and will have a cake tin cover

The front of the ally boss will be tapped to take the studs which fasten to the gear box half coupling

You may be able to disassemble the boss and remove coupling face to re tap the stud holes

Suggest you mark the boss before splitting to make sure it goes back on same as came off

Golden arrow marine may have more info and vetus have made similar units best of luck

Thanks scottie. I think you're right. It looks as if the aluminium plate fastens to the metalastic arrangement with 6 (or 8) through bolts and nuts. The propshaft pushed back okay and there is the space to remove the nuts and bolts to free the aluminium front plate.

I can't imagine anything going 'boing!' if we split the arrangement. Anyone disagree?

Thanks for taking the time.

 

[david_bagshaw]

Silent Block Coupling

It is a silent block coupling, of 70s origin. used with installations on flexible mounts.

we had 2 on a pair of Daimler Benz om314 and b warner boxes

depending on the distance behind the prop shaft is pushed back and in the middle is a nut to undo and a tapered shaft boss and key. (well ours did) scotties description is correct, centre boss and radial rubbers

do not dissemble the the aluminium bit unless you wish to replace the coupling with a new one, as it is almost impossible to get it together to run true again.

pm me & I will give you a tel no for further details of how to get a good shaft alignment with this item as it is sufficiently squashy to have no real idea of the shaft alignment.

 

[stuhaynes]

It is a silent block coupling, of 70s origin. used with installations on flexible mounts.

we had 2 on a pair of Daimler Benz om314 and b warner boxes

depending on the distance behind the prop shaft is pushed back and in the middle is a nut to undo and a tapered shaft boss and key. (well ours did) scotties description is correct, centre boss and radial rubbers

do not dissemble the the aluminium bit unless you wish to replace the coupling with a new one, as it is almost impossible to get it together to run true again.

pm me & I will give you a tel no for further details of how to get a good shaft alignment with this item as it is sufficiently squashy to have no real idea of the shaft alignment.

Hi David, PM sent - thanks, Stu